In color television broadcasting such as NTSC/PAL (EBU), R, G, B chromaticity points and a standard white point are defined for each broadcasting system. A TV video image is adjusted in color based on those defined colors, and then broadcasted. Thus, a predetermined color (white) is expected to be displayed on a display device. When a video image is to be displayed on a display device, such as a liquid crystal display, based on digital RGB video data, a general practice is to cause the display device to perform color adjustment on white through γ correction, and to thereby display the predetermined white.
However, some display devices are not capable of performing hue adjustment (γ correction). In a display device described in Patent Literature 1 given below, RGB video signals are subjected to image processing before being inputted to the display device. Main constituents of this display device include an acquisition unit (an illuminance sensor), a converter (a controller), a correction unit (a color correction circuit), an output unit (a display device), and a storage unit (RAM).
FIG. 16 is a diagram showing an example of input-output characteristics based on the technique of Patent Literature 1 given below. Chromaticity coordinates for displaying white on the display device are acquired. Then, correction coefficients are obtained for respective RGB in order for the display device to output predetermined white, and the intensity of each of RGB video signals is thereby corrected. As FIG. 16 shows, the RGB correction coefficients are determined so that the largest value may be 1.0 while maintaining the ratio among the coefficients for the purpose of outputting the predetermined white. The input-output characteristics are represented by only straight lines. Accordingly, the correction coefficients have linear inclinations. Since the ratio among RGB is maintained at a constant value over the entire input region, there is an advantage that the predetermined white can be outputted no matter what the input may be.    [Patent Literature 1] Japanese Patent Application Publication No. 2007-241120